general-filter

name	general-filter
description	Reference documentation for the GeneralFilter operator. Covers the constructor, rule-based filtering logic, and pipeline usage notes. Use when: filtering rows based on column value conditions that can be expressed as lambda functions without LLM calls.
trigger_keywords	["GeneralFilter","general-filter","rule-based filtering","conditional filtering"]
version	1.0.0

GeneralFilter Operator Reference

GeneralFilter filters DataFrame rows using a custom rule list, combining all rules with AND. It does not add new columns — it only removes rows that do not satisfy all conditions.

1. Import

from dataflow.operators.core_text import GeneralFilter

2. Constructor

GeneralFilter(
    filter_rules=[
        lambda df: df["score"] >= 4,
        lambda df: df["text"].str.len() > 10,
    ]
)

Parameter	Required	Default	Description
filter_rules	Yes	None	List of rules; each rule is a callable with signature (df: DataFrame) -> Series[bool]

Each rule returns a boolean Series the same length as the DataFrame; True means keep the row. Multiple rules are combined with AND.

3. run() Signature

op.run(
    storage=self.storage.step(),
)
# returns: "" (empty string)

Parameter	Required	Default	Description
storage	Yes	None	DataFlowStorage step object. The operator reads a DataFrame from here and writes the filtered DataFrame back.

Note: run() has no input_key / output_key parameters. Column names referenced in rules are written directly in the lambda.

Return Value

The method returns "" (empty string).

4. Actual Runtime Logic

The source code behavior is:

1. Read the DataFrame from storage.read("dataframe").
2. Initialize a boolean mask as pd.Series(True, index=df.index).
3. For each rule in filter_rules:
   • Validate the rule is callable.
   • Call cond = rule_fn(df).
   • Validate cond is a boolean Series.
   • Update mask: mask &= cond.
4. Filter the DataFrame: filtered_df = df[mask].
5. Write the filtered DataFrame back via storage.write(filtered_df).
6. Return "".

Key Behavior Notes

1. Each rule must return a boolean pd.Series; otherwise raises ValueError.
2. Columns referenced in rules must already exist in the current step's DataFrame.
3. Only removes rows; adds no new columns.
4. Multiple rules are combined with AND — only rows satisfying all conditions are kept.

5. Pipeline Usage Pattern

from dataflow.operators.core_text import GeneralFilter
from dataflow.utils.storage import FileStorage

class MyPipeline:
    def __init__(self):
        self.storage = FileStorage(
            first_entry_file_name="./data/input.jsonl",
            cache_path="./cache",
            file_name_prefix="step",
            cache_type="jsonl"
        )

        self.filter = GeneralFilter(
            filter_rules=[
                lambda df: df["score"] >= 4,
                lambda df: df["text"].str.len() > 10,
            ]
        )

    def forward(self):
        self.filter.run(storage=self.storage.step())

if __name__ == "__main__":
    pipeline = MyPipeline()
    pipeline.forward()

Note: forward() has no return value, following the standard pipeline pattern.